When her husband is killed in a railroad accident, leaving no pension or provision for the future, Daisy Hopewell opens a bakery with her three sons and sells doughnuts in northern Utah Territory in 1869. With the help of friends in the Union Pacific Railroad, Daisy secures a great location for her bakery at Promontory Point. Everyone converging on the Utah plains knows that when the Union Pacific and the Central Pacific Railroad lines join, history, as well as fortunes, will be made.

The Hopewells just want enough profit to pay off some bills. Alex, the oldest, believes it is his responsibility to take care of his mother and his brothers. But nothing is simple. His younger brother Cyrus shirks his responsibility by trying to dream up new-fangled contraptions, a blonde-haired girl complicates Alex's life, and some menacing gunmen hide a mysterious package at the family's bakery. In the midst of almost losing everything, the Hopewells find that the Lord has had a plan all along, a plan that is even more exciting than the historic event they are allowed to witness in this final installment of the Adventures on the American Frontier series.